Workholder



n Feb. 20,1934. 14R. TILLMAN 1,947,957

' .WIORKHOLDER med Aug. 11. 1952 INVEN TOR.

Patented Feb. 20, 1934 UNITED STATES WORKHOLDER John R. Tillman, Bridgeport, Conn.. assigner to The Bullard Company, a corporation of Connecticut Application August 11,

14 Claims.

This invention relates to a work holder or rlxture of the type used for metal working apparatus such as' lathes, grinders, milling machines or the like. f

It is among the prime objects of the present invention to provide a novel, simple, efficient and effective work holder which, while being adapted for manualoperations, is particularly designed for power operation. v y

Another object is to provide a work holder which will positively retain the work and which after operated to work retaining position will not slip therefrom nor transmit the holding pressures to the operating mechanism.

`A further object is to provide a fixture for retaining hollow cup-like bodies and is particularly designed to internally grasp such bodies, leaving the full outer surface thereof exposed for metal working operations.

A further object is to provide a work holder which is so arranged as to automatically insure the proper alignment of the work with the holder so that apertures of the work will be properly grasped and secured by the holder.

A further object is to provide a work holder which includes a reciprocating body having radially moving means which automatically operate in conjunction with the reciprocation of the body so as to be extended therefrom to grasp t the work and to move thereafter with the body For-purpose of illustration, the invention isv disclosed as formed to accommodate a piston blank. In this particular form of the invention. the device consists of a rotatable face plate carried for rotation with a conventional type work spindle. Associated with the face plate is a reciprocable body adapted to be actuated by crank actuating members which in turn are actuated by-a longitudinally extending actuating rod. V

An important feature of the invention is the fact that the rod to crank relationship is such that after the parts are operated, strains will not ypass back through the cranks to the rod. This is made possible by. a particular cam surface design as will be hereinafter discussed. The upper end of the actuating rod has a lost-motion 1932. Serial No. 628.312

connection with pivoted toggle-like work engaging arms which in the present embodiment of the invention are adapted to be received within the gudgeon pin openings of a piston blank. Another feature of the invention is the. provision of an arm operating means which, as in the case of the crank operator, will not transmit holding strains back through to the operating mechanism. The illustrative embodiment of the invention also includes camming end surfaces which are adapted to be engaged by the gudgeon pin bosses ofthe blank. In the operation of this form of the invention, the operating'rod may be spring urged in a releasing direction. Thus, the body actuating cranks are normally held in a manner to retain the body in an inward position against the tension of body springs and the upper ends of the pivoted toggle-like engaging arms are forced apart at the entrance therebetween of a forcing wedge moved with the operating rod. The rod is adapted to move upwardly against the tension of its` spring by a cam which movement releases the inner end of the body holding cranks, thus releasing the body and allowing it to move outwardly under the influence of the body springs and thus the engaging arms are moved, relieving the pressure on the work piece. Further movement of the operator will cause the upper-ends of the arms to move together, thus releasing the gudgeon pin apertures. At the same time, spring-urged ejector pins act to kickv out the work from the work holder.

With reference to the drawing:

Fig. 1 is a vertical sectional `view of one specinc embodiment of the present invention.

Fig. 2 is a side elevation taken at right angles to the plane of the section of Fig. 1,-and

Fig. 3 is a top plan view.

Referring more particularly to the drawing, a conventional type of work spindle is indicated by the numeral 10. Suitable driving means are provided for the work spindle as indicated by the gear 11 which is keyed thereto and secured by a securing nut l2. Obviously. this structure is merely a representative of conventional work spindle and the invention is not confined to any particular structure thereof.

The spindle is illustrated as being tubular and being provided at its lower end with an enlarged socket 13 which is adapted to receive a spring 14. The latter encircles the lower end of van operating rod l5 having an enlarged head 16, against' which the spring 14 thrusts, thus normally urging the rod in a downward position. The head 16 also acts to receive the operating thrust from a cam or similar operating mechanism such as indicated at 17.

The head 18 of the spindle has secured thereon as by bolts 19 a work fixture face plate 20. The head 18 and the face plate 20 are cooperatively recessed to provide ample space therebetween for the mechanism of the work holder as will be hereinafter described.

The upper end of the operating rod 15 has secured thereon as by the threads illustrated, an operating head 21 opposite sides of which are cut away to provide grooves 22 which permit the inward movement of the lower ends of the body holding crank when the rod is elevated. The grooves 22 terminate in outwardly extending cam surfaces 23 which in the normal downward posi,

ried by the face plate 20. This position of the cranks is illustrated in Fig. 1. It will be noted that the angle of the surface 23 is less than the angle of repose. It is important that the cam be so designed since the result will be that after operation thereof, to move the cranks, back pressure tending to reverse the movement of the cranks will not be transmitted as a force acting to move the operating rod. Thus, it will be noted that the rod and its spring will not be under the work holding strains and after movement thereof to operate the parts, no continued force will be required to keep the parts in work holding position.

The cam-like cranks 24 are of general semicircular configuration being provided with inwardly extending upper ends having projections 2 6 which upon rocking movement of the cranks engage a ange 27 of a cylindrical shell-like body 28. As illustrated, body springs 29 are provided mounted within recesses within the flange 2.7 and bearing against the head 18 of the spindle, thus normally urging the body upwardly.l Across the upper end of the body 28, a pin 30 extends and forms a pivotal support for a pair of gudgeon pinion aperture engaging arms 31, each of which are provided with right angularly extending nose pieces 32 which upon outward movement of the upper end of the rod, are adapted to engage the gudgeon pin openings 33 of the work piece 34. With the operating rod in downward position, it will be noted that the upper ends of the arms 31 are moved outwardly and retained in that position by interposition therebetween of a cross-bar 35 which extends between the bifurcated portions 36 of the outward extension of the operating rod head 21. It is important to note that after initial inward movement of the bar V35 which cams the nose pieces outwardly, the bar moves in behind the fiat inner surfaces of the arms, its at sides lying'parallel therewith. Thus, inward pressure of the nose pieces will not tend to cam the bar 35 and thus no holding strains will be transmitted therethrough to the operating bar. The outward extension also carries a cross-bar 37 which upon upward movement of the operator engages between the lower tapered end 38 of the arm 31 and thus moves them apart, retracting the nose pieces 32 so as to withdraw them from the gudgeon pin aperture.

It will be noted that the face plate 20 extends upwardly to form a housing for the body member, the side pieces thereof terminating in cam- -ming points from which the end wall sweeps downwardly to form camming surfaces 41. In the center of the end.- portion 42 spring urged of the arms. This feature of the invention 1nsures rapid and accurate placing of the work on the work holder.

Another feature of the invention is that the work holder may be operated manually regardless of the action between the cam 17 and the head 16. This is illustrated in Figs. 2 and 3. The head 21 of the operating rod is provided with a rack surface 43 preferably at right angles to the grooves 22. `Meshing with the rack 43 is a pinion 44 mounted upon a transverse shaft 45 as shown in Fig. 2. The shaft terminates with a suitable operating head such as shown at 46, it being obvious that by the application of a crank thereto, the shaft may be rotated, thereby rotating the pinion which by engagement with the rack correspondingly reciprocates the operating rod so that its operations are not wholly dependent upon automatic operating means.

In the operation of the device commencing with the parts in position as illustrated in Fig. 1, it will be noted that by movement of the cam 17 it will engage the head 16 upwardly thrusting head 21 upwardly whereby its cam surfaces 23 will release the outward thrust on the lower end of the crank 24 which lower ends will move inwardly to be received in the groove 22, thereby causing a rocking movement of the cranks on their pintles 25 so that the upper end 26 releases the flange 27 of the body 28. The body will move slightly upward under the influence of the springs 29, it being only necessary that such movement is suiiicient to release the inward pressure by the nose pieces 32 in the gudgeon pin apertures. Further upward movement of the rod 15 will cause the withdrawal of the bar 35 from between the upper ends of the arms 31 whereby they are free to move inwardly which movement will be subsequently caused by the continued upward movement of the rod. when the cross-bar 37 engages between the lower end of the arms 31 thus moving them apart and thus withdrawing inwardly the nose pieces 32. It will, of course, be noled that an elongated aperture is provided in the head piece of the operating mechanism so that such movement may be had without disturbing the pini-.le 30 of the cross arms. At the end of the upward movement of the rod, it will be noted that the ejector pin 47 carried by the end of the head of the operating mechanism will move outwardly to strike the inner end of the work piece 34 thus kicking it outward which movement will be aided by the outward thrust of the spring urged ejector members 42.

When the work holder is to be loaded the work` piece is moved axially over the work holder, its registration being insured by the camming action of the surfaces 41 whereby the gudgeon pin apertures are caused to automatically be aligned with the direction of outward movement of the nose pieces 32 as heretofore described. With the work piece in this position, the downward movement of the operating rod will rst cause the bar 37 to ist be removed from between the inner ends of the arms, thus permitting them to be moved outwardly by further movement of the rodcross-bar of which will enter between the upper ends of the arms, thus forcing them outwardly. With the arms thus forced outwardly with the noses 32 in the gudgeon pin apertures, it will be seen that further movement of ihe rod will cause the parts to assume the position of Fig. 1. During such movement, the lower ends of the cranks are forced outwardly, thus moving inwardly their upper ends, which rocking movement causes the under surface of the end 26 to move downwardly,`

whereby they engage the upper surfaces of flange 27, moving the body downwardly, against the tension of its spring 29, which movement carries with it the cross-arms whereby their lower surfaces engage the work and move it down for firm securement against the face-plate 20.

Having thus described the structure and operation of one specic embodiment of the present invention, it will be understood that the invention is not limited to the specific application orv structural embodiment herein presented. Obviously, the work holder may be used in connection with various parts with various types of metal-working machines, and the invention is not even limited to its application to metal-working machines. It is further obvious that the invention is not limited to a structure specincally designed for the securing of a piston blank since` it is withinthe scope of the invention to be applicable to various types o1' work holding requirements. v

Having thus 'described my invention, what I claim is:

'1. In a work holder, the combination of anaxally moving body, a pair of work-engaging arms pivotally mounted within the body, their -ends being adapted to extend through the walls said arms, whereby said operating means will reciprocate said body axially and independently thereof move said arms.

3. In a work holder, the combination with a body adapted to receive the work thereabout of extending side pieces forvsaid body having cam ends `adapted to engage inward extensions of a work piece so Aas to rotate the workpiece into predetermined alignment with said body.

4. In a workl holder, the combination with a body adapted to receive the work thereabout of extending side pieces for said body having cam ends adapted to engage inward extensions of a work piece so as to rotate the work piece into predetermined alignment with said body, and means'io reciprocate said body.

5. In a Work holder, the combination with a body adapted to receive the work thereabout, of 'extending side pieces for said body having cam ends adapted to engage inward extensions of a work piece, so as to rotate the work piece. into predetermined alignment with said body, and spring urged ejector pins carried by said side pieces.

6. In a work holder, a reciprocable operating means, a body, means. to reciprocate said body by said operating means, a pair of arms pivotally mounted with said body, a lost-motion connection between said arms and said operating means independent of said means to reciprocate said body, whereby movement of said operating means will cause the successive reciprocation of said body and pivotable movement of said arms.

7. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by said reciprocable body, an operating means for said reciprocable body, a cross-bar carried by said operating means, said cross-bar being arranged to engage said arms to move them to work operating position.'

8. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by said reciprocable body, an operating means ,for said reciprocable body, a pair of cross-bars carried by said operating means, one of said cross-bars being arranged to engage said arms to move them to work operating position and another of said cross-bars adapted to move said arms to work disengaging position.

9. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by-said reciprocable body, an operating means for said reciprocable body, a cross-bar carried foov by said operating means, said cross-bar being arranged to engage said arms to move them to work operating position and means to prevent said arms from moving said cross-bar.

10. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by said reciprocable body, an operating member for said reciprocable body, a pair of cross-bars carried by said operating means, one of said cross-bars being arranged to engage said arms to move theml to work operating position and another of said cross-bars adapted to move said arms to work disengaging position, and automatic means to move said operating member.

11. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by said reciprocable body, an operating member for said reciprocable body, a pair of cross-bars carried by said operating means, one of said cross-bars being arranged to engage said arms to move them to work operating position and another of said cross-bars adapted to move said arms to work disengaging position, and manual means to operate said operating member.

12. In a work holder, the combination of a reciprocable body, a pair of pivoted arms carried by said reciprocable body, an operating member for said reciprocating body, a, pair of cross-bars carried by said operating means, one of said cross-bars being arranged to engage said arms to move them to work operatingA position and another of said cross-bars adapted to move said arms to work disengaging position, and manual and automatic means to operate said operating member.

13. In a work holder, the combination of a reciprocable body, a. pair of pivoted arms carried by said reciprocable body, an operating member for said reciprocable body, a pair of cross-bars carried by said operating means, one of said cross-bars being arranged to engage said arms to move them to work operating position and another of said cross-bars adapted to move said arms, to work disengaging position, and spring means for normally urging said operating means to work engaging position. f

14. In combination with an axially rotatable tubular work spindle, a-face plate carried thereby, a reciprocable body mounted within said face lost-motion connection between said arms and said rod whereby downward movement of said rod will cause said arms to engage a work piece, and means on said body to automatically insure alignment of a work piece with said arms.

JOHN R. TILLMAN.l 

